Machine for making cushioned pads



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Dec. 9, 1952 R. A. WETHERELL 2,620,854

MACHINE FOR MAKING CUSHIONED PADS Filed Sept. 50, 1948 4 Sheet s$heet l m z a? ,9 1 f9 fig 1952 R. A. WETHERELL 2,620,354

MACHINE FOR MAKING CUSHIONED PADS Filed Sept. 50, 1948 4 Sheets-Sheet 3 19? 106 /@::n :6 9 l 4 1% 1a Q a o E, 3100 Patented Dec. 9, 1952 MACHINE FOR MAKING CUSHIONED PADS Russell A. Wetherell, Attleboro, Mass, assignor to The Mason Box Company, Attleboro Falis, Mass, a corporation of Massachusetts Application September 30, 1948, Serial No. 52,110

4 Claims.

This invention relates to an improved machine for applying a flexible covering material of an ornamental or decorative character to a relatively stiff backboard and more especially to a backboard having on one surface a cushioned material to form a cushioned pad for use in jewelry boxes and the like. The principal object of the invention is to provide a machine which will efiect wrapping of the pads without wrinkling, at the corners rapidly; efiiciently and with a minimum of skill required on the part of the operator according to the method illustrated, in my pending application Serial No. 131,334 filed December 6, 1949 covering the article per se and its method of manufacture.

The machine illustratedherein' for making the pads has a support for holding the backboard, cushion material and covering material in superimposed relation with the marginal portions of the covering material bent into engagement with the peripheral edge face of the blackboard and wipers arranged to operate substantially in the plane of the uncushioned surface of the backboard to bend the covering material into engagement with the uncushioned surface of the backboard. The wipers include corner and side wiping members. The former are actuated to first wipe in the material at the corners of the backboard followed by the latter which wipe in the intermediate material. Movement of the wipers is effected by power operated means and delayed action linkage is interposed between the power operated means and the side wipers to cle lay their movement so that the corner wipers will perform their operations first. The support includes a forming member and a carriage, each of which has a cavity therein for reception of the superimposed backboard, cushion and covering material and are movable relative to each other to receive the backboard, cushion and covering material at a loading position, move them to a position beneath the forming member, force them into the cavity in the forming memher and hold them there until the wipers engage the under surface of the backboard. The carriage is movable from a loading position at the front part of the machine to a presenting position in timed relation with the wiping action so that while the wipers are fulfilling their operation, the carriage is moved back into loading position to receive the component parts of the pad and is in readiness for the next operation. To apply pressure while the wipersare in closed position and to facilitate removal of the finished pad, a combination pressure plate and ejector is This insures good contact of the adhesive on the backboard with the covering material. In addition, when the wipers have retracted, this coinbination pressure plate and ejector forces the pad from the cavity onto a tray which is arranged to be swung from a position beneath the forming member to an accessible position atthe front of the machine. To. insure the formation of smooth, unwrinkled corners, the cavity in the forming member has at its corners recesses into which the fullness of the covering material caused by constriction thereof where it bends around the same may expand.

The invention will now be described in more detail with reference to the accompanyingdrawings in which:

Fig. 1 is a vertical front elevation of the machine showing the carriage in loading position;

Fig. 2 is a vertical side elevation of the machine as seen from the left side of Fig. 1;

Fig. 3 is a vertical section through the forming device and carriage showing the backboard, cushion and covering material forced into the forming opening in the folding member and held therein ready for wiping;

Fig. 3 is a plan view of the folding member inverted, with the coveringmaterial forced into the opening thereinand with the fullness of the corners occupying the cavities at the corners of theforming opening;

Fig. 4 is a plan view to somewhat smaller scale showing the wiping means as seen from its" under side and in retracted position;

Fig. 5 is a vertical section on the line 5-5 of Fig. 2;

Fig. 6 is a vertical section through a fragmentary portion of the carriage;

Fig. '7 is a plan View to larger scale of the wiping means as seen from its under side with the wipers partially advanced'so that the corner wipers engage the corner portions of the covering material;

F Fig. 8 is a vertical section on the line 8-8-of Fig. 9 is a section on the line 99 of Fig. 7 showing the shape of the wiper blades;

Fig. 10 shows a fragmentary portion of a pad in a process of being covered and the formation of the fold at the corner thereof; and

Fig. 11 shows a bottom View of a completed pad.

Referring to the drawings, the machine I!) comprises essentially a forming device [2, a carriage l4, and wiping means Hi, the aforesaid appliances being assembled together in operating relation upon a frame l8.

The frame I8 is comprised of a pair of spaced channel-shaped castings 28 rigidly joined at their top ends by a pair of spaced bars 22 welded to the opposite sides thereof and a brace 24 fastened between them at their lower ends to form a rigid framework within which the operating parts may be mounted. Other shelves and supports for carrying the operating parts of the machine are fixed to and within the frame as will appear hereinafter.

The carriage [4, shown most clearly in Figs. 1, 2 and 5, is arranged to move in a horizontal plane from the front of the machine inwardly to a loading position beneath the forming device [2 on a pair of spaced horizontally disposed rails 26 which are set on edge and fixed at their opposite ends to the bars 22 so that inverted V- shaped slide ways are provided. The carriage l4 includes a flat, substantially rectangular plate 28 (Fig. to the four corners of which are fastened blocks 30 which have in their under surfaces V-shaped grooves 32 for engagement with the inverted V-shaped slide ways of the rails 26, thereby providing for sliding movement of the carriage along the rails and at the same time preventing lateral displacement. To the upper surface of the plate 28 there is fastened a platform 34 which is held spaced therefrom by a pair of spaced bars 36. The platform 34 has a shallow recess 38 in its top surface to receive and hold an adapter plate 40 having formed centrally thereof an opening 42 which extends through the plate from top to bottom and a concentrically arranged, somewhat shallow, larger recess 44 in its upper surface. The opening 42 is of a size and configuration to receive a backboard b and a cushion member 0 which form the component parts of the cushioned pad. The covering material C which is to be applied to the backboard and cushion member, as will appear hereinafter, is disposed above the cushion material 0 in the shallow recess 44 with its marginal edges m extending beyond the edges of the cushion material and backboard (Fig. 6). The shallow recess 38 in the platform 34 is open at one end to permit the adapter plate 40 to be slid off of the platform and replaced by an adapter plate having an opening of different size so that the apparatus may be used to cover different size cushioned pads. An opening 46 is formed centrally of the platform 34 so that it communicates with the opening 42 in the adapter plate 40, and in this opening there is situated a flat head 48 formed at the upper end of a post 50, the latter extending vertically downward through an opening 52 formed in the plate 28 and through a sleeve 54 fixed to the under side thereof, a keyway and key being provided for preventing rotation of the post in the sleeve. The post 50 is held at its lowermost position by gravity. Three small springs 60 are provided on the plate 28 which act as a cushion for the flat head 48 these springs being equally spaced about the post and set into recesses 6| formed in the plate and head. This spring cushion also limits the downward movement of the post by engagement with the plate 28. As thus held, the upper surface of the fiat head 48 is fiush with the upper surface of the platform 34. By moving the post 50 vertically, the backboard, cushion and covering material may be forced out of the adapter plate 40 and into the forming device II which will now be described, this being accomplished as will appear hereinafter at a time when the carriage is situated directly beneath the forming device. To insure that the carriage l4 does not bound back slightly after reaching its full forward position, which would result in the adapter plate 40 not remaining directly in line vertically with the forming device [2, a means is provided to prevent this in the form of a ledge 66 (Fig. 1) fixed to the under side of the plate 28 with which there is engaged a roll 64 fixed to the upper end of a rod 62, the latter projecting down through a hole in a bar 23 and having on it a spring 68 engaged between the under side of the bar 23 and the head of the rod. This holds the carriage firmly against the rails 26 and prevents the carriage from moving until driven mechanically.

The forming device 12 which is most clearly shown in Fig. 5 is supported above the carriage I4 by four vertically disposed posts 12 fixed at their lower ends to the upper ends of the castings 20 and by horizontally disposed bars 14 fastened to the top ends of the posts, and extending transversely of the machine which are reinforced by spaced bars I6 extending from front to back and welded to the bars 14. To the under side of the bars 16 there is welded a rectangular plate 18. There are attached to the central portion of the under side of the plate 18 a spacer member made of asbestos or other suitable material to minimize heat transmission to the top of the machine where heat is neither needed nor desirable, and a forming block 82, suitable means being provided for attaching these elements to the plate. The forming block has in it a number of passages 8i (Fig. 3) running through it from one edge to an opposite edge within which may be disposed heating elements E. The forming block also has in its lower surface and extending from front to back thereof a channel 84 having undercut lateral edges within which there is slidably disposed a folding member 86 having a substantially rectangular opening 88 formed through it in the central portion thereof which is of such size and configuration as to receive the covering member C, cushion member 0 and backboard b in the order named. The folding member 86 has in its exposed surface at each corner of the opening 88 an inclined cavity or recess 30 which originates in the vertical walls thereof and extends upwardly and outwardly through the top surface of the member. The cavity 90 is adapted to receive the excess covering material which is produced at each corner by bending the marginal edges of the covering material consistently at each corner into a point, or peak of such shape that the action of the thin edge of a wiper blade will consistently draw this excess corner material toward the center of the backboard and away from its edges, thus forming the triangular fold of covering material shown in Fig. 11. It is evident that if the size of the pad is to be changed, the folding member may be withdrawn and replaced with one having a larger or smaller opening therein. Vertical openings are formed through the forming block 82, the spacer 80 and the plate 18 through which passes a rod 92 to the lower end of which is fixed a fiat plate 94 situated with the opening 88 against the block 82 so that the covering material when forced into the opening rests against this plate. By movement of the rod 92 in a directionto forcethe. plate 94 downwardly, pressure may be applied. to cause firm contact of the adhesive on the backboard with the covering material'and also the covered backboard may be forced out of the forming device.

The foregoing appliances serve to hold the component parts of the pad in a position to be operated upon by the wipers I6. To accomplish this, that is positioning of the component parts for wiping, a backboard b is placed within the opening 42 (Fig. 6) of the carriage, cushion material c is. placed upon the backboard, and then covering material C is placed upon the cushion in the recess 44. The loading device is then moved inwardly along the rails 26 to a position directly below the forming device I2, whereupon the post 50 is raised so as to eject the backboard, cushion and covering material from the carriageand forcethe covering material, cushion and backboard-in the order named into the opening 88 of the forming device against the plate 94, the marginal edge of the covering material thereby being folded down into engagement with the edge faces of the cushion and backboard and projecting downward beyond the exposed under surface of the backboard, as shown in Figs. 3 and 3*. As thus folded there is an excess of covering material at the corners which produces puckers P. This puckering or fullness at the corners is, however. taken up by expansion of the covering material into the inclined cavities 90 at the corners of the folding member 86 which causes the covering material consistently to form peaks pointed directly toward the corner wiper blades. In accordance with this invention, while the covering material is held in this position, that is, with the marginal edges substantially at right angles to the bottom of the backboard and the corner portions thereof expanded into the cavities 90, the covering material is wiped inwardly over the exposed bottom surface of the backboard by first wiping the corner portions thereof inwardly and then Wiping the intermediate portions inwardly beneath the in-wiped corner portions. This is accomplished, as will now be described, by the wiping means I6. The in-wiped marginal edges are held in place by an adhesive as will appear hereinafter.

The wiping means I6 (Figs. 2 and 5) is fastened to the under side of the plate 78 to operate in a plane which is substantially coincident with thebottom surface of the forming block 82. To this end a pair of spaced bars I00 are fastened to the under side of the plate I8 and from these bars project downwardly four short posts I02 to the lower ends of which are pivotally fastened by means of shoulder bolts I06 arms I04, two of these being arranged at each side of the machine and between the outer ends of corresponding arms I04 at the front and rear of the machine are pivotally fastened bars I08, the connection between the arms I04 and bars I08 being made by way of slots H0 and shoulder bolts II2 so that there is a limited amount of free movement between the connected ends. The inner ends of the arms I04 at each side are pivotally connected at II4 to a pair of short links II6 which in turn are pivotally connected at II8 to a rod I20. Movement of the righthand rod I20 in a direction to the right, as shown in Fig. 7, swings the front and rear links II6 apart thereby pivoting the arms I04 in clockwise and counterclockwise directions respectively about their pivot points I06 so as to move their inner ends inwardly, and at the same time to draw the barsv I08 towardeach other. Movement of the left-hand rod' l20toward the left produces a corresponding movement of the opposite ends of the bars I08 toward each other. Movement of the rods I20 in opposite directions reverses the movement of the arms I04 thereby separating their opposite ends and moves the bars I08 away from each other. A spring I22 is fastened to the outer ends of each pair of arms I:04 at each side of the machine to eliminate sloppiness in the movement of the linkage. The wipers are operated by the aforesaid linkage as will now appear. To the bottom surface. of the forming block 82 and the folding member 86 there are fastened a plurality of guide members I24, I26 and I28 for accommodation of the wiping members, each of these guide members having undercut channels I30 therein (Fig. 7). The guide members I24 accommodate T-shaped corner wipers which comprise a shank portion I32 arranged to slide in the channel formed in the guide and a blade portion I34. The guide I24 is so arranged that it makes an angle of substantially 45 degrees with the edges of the opening 88 in the folding member 86 hence as the blade I34 is moved inwardly, its leading edge which engages the covering material at the corner will be moving in a direction substantially normal to a line bisecting the corner. The rear end of the shank I32 of each corner wiper is connected for operation to one of the arms I04 by a short connecting link I38. To prevent play in the movement of the wiper, a gib I40 (Fig. 8) is placed within the groove I30 of the guide against one edge of the shank I32 and is held yieldably pressed thereagainst by spaced springs I42 entering recesses I44 in the side of the guide and bearing atone end against the gib and at their opposite ends against an abutment I46 screwed to the block 82. The side wipers are also T-shaped and comprise a shank I48 and a blade I50, the former being slidably received in the guides I28 and being connected by pins I52 and slots I54 to substantially triangular plates I56. The triangular plates I56 are fastened by screws I58 to the bars I08. The end wipers comprise a shank portion I60 and a blade I62, the former being slidably received in the guides I26 and having their outer ends connected by pivoted links I64 to levers I66 (Fig. 5). Each lever I66 has at its free end a. follower I68 which rests in a slot I70 formed in the upper face of a block I'IZ, the latter being fastened to the'inner end of the rod I20. By reason of the aforesaid construction, movement of the rods I20 in either direction will impart immediate motion to the corner wipers to move them inwardly or outwardly but the motion of the side wipers and the end wipers will be delayed by the length of the slots I54 in the side Wiper connections and the slots I10 in the end wiper connections.

The ratios of the linkages for moving the wipers into and out. of operative position are proportioned so that the corner wipers I34 first engage the covering material at the corners of the forming device and begin to wipe the material in over the bottom surface of the backboard prior to the engagement of the side and end wipers with the covering material. In their inoperative position (Fig. 4) the blade portions of the end Wipers and side wipers I62 and I50 lie within the blade portion of the corner wipers I34. The delay action referred to above however delays the movement of the endand side wipers I52 and I50 until the blade portions of the corner wipers I34 have engaged the corners. At this time, as shown in Fig. 7, the blade portions of the end wipers I82 are behind the blade portions of the corner wipers, the latter having been moved by them. Since the blades of the end and corner wipers overlap at this point, recesses I34 are made in the end portion of the blades of the corner wipers on their upper sides next to the end wipers and corresponding recesses are made in the end portion of the end Wipers on their under sides so that one may move by the other without interference. The side wipers I50, however, do not interfere with the movement of the corner wipers since they lie ahead of the corner wipers when the latter are in engagement with the corners. The positions of the various wipers when they have completed their in-wiping movement is shown in dotted lines in Fig. '7. The wiping actions of the wiper blades in the manner prescribed starts a fold F at each corner of the excess covering material and as it is laid down (Fig. 10) by the corner wipers, the side and end wipers come in and wipe the marginal edges along the sides and ends beneath the corner folds so that while the folding at the corners starts first, the sides and ends are folded in before the corner folds are completed and lie beneath the same.

. The wipers, as shown in Fig. 9, have broad, thin, fin-like edges I18 and subjacent fiat wiping surfaces I18, all of which lie in a common plane.

It is customary to secure the wiped-in edge of the covering material to the bottom surface of the backboard with adhesive, and this is accomplished herein by previously applying adhesive to either the marginal edge of the upper material or the bottom surface of the backboard, or both, the adhesive being of a heat-sensitive type. The heating elements E keep the forming block 82 hot enough so that as the marginal edges of the covering material are wiped in over the bottom surface of the backboard, the adhesive will be activated and secure the marginal edges of the covering material in place. In addition to heat, some pressure is required. This is furnished by the combination pressure plate and ejector. When the wipers are at their "in position a downward motion of rod 92 presses the covering material and backboard against the wipers. Prior to the wipers movement toward their out position, rod 92 moves upward releasing the pressure.

After the wiping action has been completed, the finished pad is ejected from the forming block 02 by downward movement of the rod 92 and the plate 94 which forces the pad from the folding member 86 and allows it to drop onto a tray I80 (Fig. 1) fixed to an arm I82 which is carried by a sleeve I83 mounted to turn freely on one of the posts I2, the tray being automatically swung into a position to receive a finished pad and then deliver it to the front of the machine as will appear hereinafter.

The aforesaid appliances are operated in a manner to produce the desired results by poweroperated mechanism situated in the lower part of the frame. As illustrated, an electric motor M situated near the front of the machine provides the motive force and is bolted to a bracket I 84 fastened to the brace 24. From the motor M a horizontal shaft I86 extends through the right side casting and to the shaft there i secured a V-pulley I88 over which there passes a V-belt I90 to a second V-pulley I92, the latter bein secured to a. horizontal shaft I94 (Fig. 2) spaced rearwardly of the motor shaft. The horizontal shaft I94 is supported in spaced bearings I98 fastened to the top side of a shelf I 98, the latter being secured to the back of the frame. The shaft I94 is connected by way of a conventional clutch (not shown) to a shaft 208 journaled in bearings 2H) and has thereon a worm 208. The clutch may be engaged and disengaged by a conventional shifting fork 200 pivoted at 202 to a bracket 204 fixed to the rear of the frame and operated by a shift bar 20I which extends forwardly to the front of the frame and has a handle 203 fastened thereto so as to be operated from the front of the machine. Optionally, of course, a foot pedal could be used in place of a handle. The worm 208 meshes with a worm gear 2I2 which is fastened to a horizontal cam shaft 2I3 extending from front to back and journaled in spaced bearings 2I4, two of which are supported on a shelf 2I8 and one of which is supported at the upper end of a post 2H5. The shelf 2l8 is situated above the shelf I98 and rests on a pair of angles 220 fixed to the inside of the frame. The post 2 I6 is fastened to the upper side of the bracket I98 at the rear of the frame. On the cam shaft 2I3 at the back of the frame there is fixed a gear 224 which meshes with a gear 228, the latter being fixed to a short horizontal shaft 228 extending at right angles to the cam shaft 2I3, and on this short shaft there is freely mounted a block 230 which is adapted to slidably occupy a slot 232 formed in an arm 234. At each end of the slot 232 and at opposite sides of the arm are fixed cam followers 238 with which cooperate cam arms 235 which are fixed at one end to the shaft 228. These cams are so arranged that during rotation of the shaft 228 one of the cam arms 235 will operate upon one cam follower 236 to move the arm 234 linearly in one direction and the other will move the arm linearly in the opposite direction, thereby producing reciprocation of the arm. The lower inner end of the arm 234 is pivotally connected at 238 to a rocker 240, the latter being pivoted to the frame at 242 and connected at its opposite end by a link 243 to the under side of the carriage I4. Reciprocation of the arm 234, therefore, will rock the rocker 240 and hence move the carriage I4 along the rails 26 from loading position to operative position and vice versa. As soon as the carriage has been moved to a position directly below the forming device, the covering material, cushion and backboard are ejected from the carriage and forced into the forming device by vertical movement of the post 50, and this is effected when the loading device is in this position by a "cam 244 fixed to the shaft 2 I3 within the frame which has a cam track 246 thereon. A cam roll 248 fixe in one arm of a bell crank lever 250 pivotally supported in the frame at 252 bears against the cam track 246 and rotation of the latter operates to tilt the bell crank lever about its pivot point and to move its other arm substantially vertically. The terminal end 254 of this arm is arranged to engage the lower end of the post 50.

Operation of the wipers is effected by a pair of cams 256 and 258 fastened to the cam shaft 2I3 within the frame which have in their opposite surfaces cam grooves 280 and 252 respectively, within which operate cam followers 264 (Fig. 1) fixed to the ends of slide rods 286, each of which is slidably mounted in spaced brackets 288 fastened to the top of the shelf 2I8. The outer ends of the slide rods are pivotally connected to vertically disposed rocker arms 210 pivoted to the sides of the frame at 2'12, and their upper ends are pivotally connected at 274 to the rods 129. Rotation of the cam shaft 21s will, therefore, by way of the cams 256 and 258 impart reciprocation to the rods I29 to move the wipers inwardly or outwardly,

During the time when the wipers are at in position, pressure must be applied and following the completion of the wiping operation, the completed pad must be ejected from the forming device. Both of these operations are accomplished by downward movement of the rod 92. Movement of the rod 92 is effected by a cam 2'55 (Fig 2) mounted on the cam shaft 2 13, just inside the frame, upon which rides a cam follower 2'38 pivotally mounted at the lower end of a cam rod 289. The rod rises vertically through a sleeve 2S2 fastened to the frame and has connected to its upper end at 284 a lever 286, the latter being pivoted at 288 to a post 239 fixed to one of the bars '85. A tension spring 299 connected to the rod 289 and to the frame normally holds the lever 286 in a retracted position. Upward movement of the rod 280 produced by a high spot in the cam surface 216 Will tilt the forward end of the lever 285 down and, by way of a ball 292 situated at the upper end of the rod 52, will bring about depression of this rod. The rod is guided in its movement by a bracket 294 and is returned to inoperative position by the spring 99.

The tray 1811 for receiving the ejected pad is normally held beneath the forming device 82 by a spring 131 attached to the free end of an arm I85 which is fixed to the sleeve 18?. To effect movement of the tray, a rod 18'! (Fig. 2) having a bifurcated forward end I99 is pivotally attached to the arm I85. The rear end of the rod is also bifurcated and is connected to one arm of a bell crank lever 19!, the other arm of which has a horizontal projection thereon to which is fastened a cam roll for engagement with the cam surface I93. The cam surface I93 is shaped so that the bell crank lever will oscillate the rod I81 in timed relation with the carriage so that as soon as the latter moves to loading position the tray will move to a position to receive the ejected pad, and as the carriage moves into ejecting position the tray will swing out to the front of the machine to discharge the pad.

In the operation of the aforesaid machine, the carriage I4 is first brought to a position at the front of the machine, as shown in Fig. 2, the backboard b is placed in the opening 42, cushion material is placed above the backboard, and a suitable covering material C is then placed above the cushion in the recess M as shown in Fig. 6. The handle 203 (Fig. 2) is then rotated to operate the clutch and hence to connect the main cam shaft 2l3 to the continuously rotating worm gear 212 so as to effect rotation of the cam shaft 213. Thereafter, because of the specific arrangement of the various cams which impart movement to the parts, the formation of the pad is effected first by movement of the carriage I l inwardly to a position directly below the forming device I2 then by movement of the post 59, and hence the head 48, which lifts the backboard, cushion and covering material from the loading device and forces them into the forming device; then by movement of the wiping member 16 inwardly to fold the marginal portions of the covering material into engagement with the bottom side of the backboard; then by movement of rod 92 and plate 94 to provide pressure to insure good contact of adhesive; then by withdrawal of the wiping members; and finally by movement of the rod 92 and plate as to eject the finished pad onto the tray :89 whereupon the tray is operated to bring the pad to the front of the machine. The moving parts are timed so that during the wiping movement of the wipers the carriage IQ is moving back to loading position to receive a new charge of material and the tray 189 is moving beneath the forming device so as to be ready to receive the finished pad when it is ejected from the forming device, and that during movement of the tray to an out-of-the-way position, the carriage which is now loaded will be moving inwardly into ejecting position. As long as the clutch is left engaged, the machine will continue automatically provided the operator loads the carriage each time that it arrives at the front of the machine. Discontinuance of the operation of the machine may be effected by declutching the clutch.

It should be understood that the present disclosure is for the purpose of illustration only and that this invention includes all modifications and equivalents which fall within the scope of the appended claims.

I claim:

1. In a machine for applying a covering piece to a polygonal backboard to make a covered pad, said piece being larger than the backboard by a margin extending around its periphery, the combination of a holder having a polygonal opening to receive said piece and cardboard in superposition with said margin projecting past the edges of the cardboard and beyond the edges of the opening, the corners of the opening being recessed beyond the outline of the polygon to receive the fullness of the said margin at the corners, side and corner wipers to fold the side and corner portions of the margin over the backboard, and means to actuate said wipers in sequence so that the corner folds overlap the same faces of all the side folds.

2. A machine according to claim 1 further characterized in that said means actuates the wipers so that it is the outside faces of the side folds which are overlapped by the corner folds.

3. A machine according to claim 1 further characterized in that said means causes the corner wipers to start the corner folds before the side wipers start the side folds.

4. A machine according to claim 3 further characterized in that said means completes the movement of the side wipers before completing movement of the corner wipers.

RUSSELL A. WETHERELL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 513,453 Coles et al Jan. 23, 1894 1,073,324 Bredenberg Sept. 16, 1913 1,326,827 Anthony Dec. 30, 1919 1,336,944 Dean Apr. 13, 1920 1,591,724 Mitchell July 6, 1926 1,622,035 Hendel Mar. 22, 1927 1,640,515 Ohlsson Aug. 30, 1927 1,811,871 Anthony June 30, 1931 1,960,475 Canfield May 29, 1934 2,156,059 Marsack Apr. 25, 1939 2,458,588 Gordon et al. Jan. 11, 1949 

